The hypoglycemic activity of CI-991 has been demonstrated in patients with sulfonylurea resistant NIDDM. This study is designed to compare the efficacy of troglitazone as monotherapy and troglitazone in combination with micronized glyburide in patients who are currently taking the maximum dose of sulfonylurea with a submaximal response. Changes in the markers of glycemic and lipid homeostasis are being assessed as well as long term safety.